1. Field of the Invention
The present invention relates generally to air flow modulating devices, and more specifically to air flow modulating devices that operate mechanically to adjust air flow.
2. Background Information
Air intake terminals and devices are well known. Air intake terminals or devices may be used in conjunction with fuel-fired or sealed combustion condensing appliances, particularly heating appliances. Generally, fuel-fired or combustion heating appliances have intake and venting terminals. These terminals may comprise conduits that have one end attached to the combustion heating appliance and one end connected to an air source external to the area or building being heated by the heating appliance.
Fuel-fired or sealed combustion condensing appliances require a constant draft of air for proper operation and efficient consumption of fuel. The draft through a fuel-fired or sealed combustion condensing appliance may be affected by pressure differences across the appliance. For example, numerous changes in environment may cause pressure changes at, and through, the air intake terminal. Such changes include, but are not limited to, wind induced pressure effects, changes in ambient barometric pressure, debris caught in an intake terminal and/or ice or snow blocking the intake conduit. These environmental changes may be undesirable because they affect the desired pressure differential across the air intake terminal and air venting terminal.
While the prior art has provided examples of features of air intake terminals and devices that people find useful, there is always room for further improvement.